1. Field of the Invention
The present invention relates to safety apparatus for protecting the head and neck of the occupant of a motor vehicle to reduce the extent and severity of injuries sustained during a side impact crash. More specifically, it relates to a system of components that inflate to cushion the head and neck from direct impact with the interior structure of the vehicle.
2. Background of the Invention
Side or lateral impacts are a leading cause of injuries and fatalities in automotive crashes. According to the Insurance Institute for Highway Safety (IIHS), 30 percent of all automobile occupant fatalities in the United States in 1989 involved side impact crashes.
Occupants killed in side impact crashes typically have a high incidence of head and neck injuries. Side impact crashes also cause severe injuries to other body regions including the chest, abdomen, pelvis and extremities. FIG. 1 summarizes the distribution of injuries by body region, based on an IIHS study of 91 struck-side and 49 opposite-side fatalities in the United Kingdom in 1985. FIG. 1 shows the distribution of greater than 3 on the Abbreviated Injury Scale (AIS) by body region for fatalities in struck-side and opposite-side crashes. "Struck-side" refers to occupants seated on the side of the vehicle that was struck, while "opposite-side" refers to occupants who were seated on the side that was not struck. According to the IIHS study, 64% of struck-side occupants suffered head injuries; 12% suffered neck injuries; 85% suffered chest injuries; 26% suffered pelvis injuries; 2% suffered injuries to their upper limbs and 21% to their lower limbs; and 59% suffered abdomen injuries. FIG. 1 also shows that 82% of opposite-side occupants suffered head injuries; 20% suffered neck injuries; 73% suffered chest injuries; 14% suffered pelvis injuries; 10% suffered injuries to their upper limbs and 12% suffered injuries to their lower limbs; and 49% suffered abdomen injuries. FIG. 1 shows that serious head and neck injuries can occur in either seating position.
Conventional automotive safety belt and air bag systems offer inadequate protection to the head and neck in side impact crashes. These systems are generally designed to protect occupants from primary injuries sustained only in frontal impacts, or in oblique impacts up to approximately +/-30 degrees.
Federal Motor Vehicle Safety Standard (FMVSS) 214 currently defines the test procedures and performance requirements for occupant protection in side impact crashes. The dynamic requirements of FMVSS 214 are scheduled to be phased into practice based on an escalating percentage of each manufacturer's annual production starting Sep. 1, 1993.
In response to FMVSS 214, several developments in side impact countermeasures have occurred. These countermeasures primarily include the reinforcement of side components and door structures with improved door beams, modified pillars, and improved energy-absorbing door padding.
All of these developments in response to FMVSS 214 focus on limiting the intrusion of an object into the passenger compartment. Additionally, energy-absorbing padding helps distribute the impact force to the struck-side occupant over a larger surface area. An excellent production example of these technologies is the side impact protection system incorporated into current Volvo automobiles which carries door beam loads through the front seats into a center tunnel structure.
Another countermeasure recently being considered by several vehicle manufacturers are air bags that deploy from the door panel to provide protection for the thorax, abdomen and pelvic regions. These systems help distribute the impact force over a larger body surface area to reduce the extent and severity of injuries sustained during a side impact crash. However, these systems are not expected to provide significant protection to the head, face and neck. Therefore, as increasing numbers of vehicles are equipped with these countermeasures, head injuries will likely emerge as the predominant injury in all side impact crashes.
There are three major causes of head, neck, and face injuries in side impact crashes:
(1) The head and neck regions strike the upper interior side components of the vehicle. These components include the upper door frame, the A and B-pillars, the roof rail and the upper door frame. FIG. 2 shows the relative positions of A-pillar 20, B-pillar 21, roof rail 23, and upper door frame 25.
(2) The head and neck regions collide with the striking (or struck) object.
(3) The head flailing through the window frame. Typically, the side window is shattered early in the impact, and is therefore not a strike hazard. However, the head of the occupant is not restrained inside the passenger compartment. Moreover, the window cannot be used as a load bearing surface for a conventional type of air bag.
In light of these potential dangers, an effective side impact head and neck protection system must prevent or cushion the head from directly colliding with the upper side components of a vehicle, cushion or prevent the head and neck from directly being impacted by the striking or struck object, and restrain the head inside the confines of the vehicle.